The present invention relates to mechanisms for controlling the passage of solar radiation to maximize solar gain in winter and provide shade in summer.
A wide variety of devices have been developed with the objective of increasing the utilization of solar energy in housing and other structures. In the summer, it is generally desirable to shade the structure to reduce solar energy input, thereby decreasing the requirement for air conditioning, which generally relies on fossil fuel resources either directly or indirectly. In winter, the goal is to achieve direct solar input into the interior of the structure, maximizing the heat input and reducing heating requirements, which again generally rely on fossil fuel resources either directly or indirectly.
Most devices for increasing solar energy utilization in building structures are directed solely to either summer or winter usage. In other seasons of the year, the system- must contain some sort of mechanism for rendering it nonfunctional. For example, a structure may be designed with a large window area and considerable inside thermal storage to maximize solar energy utilization during the winter--but in summertime, the windows must be provided with a shade so that the structure does not become overheated and require excessive air conditioning. As a second example, louver systems have been designed which block direct sunlight to provide shade in the summer, but in the winter such shading is undesirable. There has been a significant dearth of systems which are efficient controllers of solar energy both in the summer and in the winter.